


Sizing

by razielim



Series: Merry Smutmas 2016 [5]
Category: Voltron: Legendary Defender
Genre: Anal Gaping, Double Penetration, M/M, Sex Toys, Vibrators
Language: English
Status: Completed
Published: 2016-12-25
Updated: 2016-12-25
Packaged: 2018-09-11 00:09:12
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,393
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8944843
Author URL: https://archiveofourown.org/users/razielim/pseuds/razielim
Summary: Shiro's no slouch in the size department, but keeping up with a size queen sometimes means you have to put your creativity and engineering skills to good use.for theyullenator





	

Keith moaned again, louder, as he dipped a finger into himself alongside Shiro’s cock. Shiro slowed down, afraid of hurting himself or Keith on a nail, even though he knew Keith meticulously clipped and filed. 

“No, faster-”

“Pull your finger out-”

“No, I need to be fucked open, Taka-

“Pull it out so I can go full speed.”

Keith obeyed, though not without a whine of complaint. Shiro braced one hand on Keith’s lower back and picked up speed, thrusting in deeper than he normally allowed himself to. Mewling and pushing back, Keith dug his fingers into Shiro’s hip. He was always asking to take Shiro’s length in its entirety, so now he was going to get it, Shiro drilling harder and further than usual until Keith was gagging on his moans. 

Shiro pulled out, chest heaving, to assess his work. Keith’s gaping hole, burgundy and perfectly round, clenched around air, begging to be filled again. He let his cock tease around the entrance for a bit until Keith complained, then pushed back in, fucking so fast Keith couldn't even moan right, his cries continuous and needy. 

Pulling out again, Shiro backed away, slipping off the bed and staggering, disoriented by need. Keith pushed up to look back at him. 

“What’s wrong?”

Shiro shook his head, eyes on that greedy hole. 

“Stay there, I have a surprise.”

Effortlessly obedient, Keith sighed and put his face back in the pillow. Shiro had trained him well to give in to orders, always making it worth his while. 

Rifling through the bag where he’d hidden it, Shiro hoped this would please Keith the way he needed. He had been working on this surprise for a while, and had even involved the embarrassment of asking Hunk for help. Pidge might have been better for this sort of thing, but he'd known her since she was a child so that wasn’t an option. Even with Hunk, he'd never managed to explicitly say what it was he was aiming for as an end result. Though he had no doubt Hunk was smart enough to guess. 

Shiro unwrapped the gift carefully, watching Keith’s ass wiggle impatiently. Unable to resist, he came up close to push a curious finger around the rim, causing Keith to moan and buck. He pulled his finger away to press the device under his own cock, lining up the lengths and fastening the straps. 

The device came to life with a soft whirr when he flipped the switch with his thumb. Thousands of years of Galra and Altean technological advancements, and Shiro was about to use that vast knowledge for the most base of purposes. 

He pushed forward, watching with fascination as Keith’s already well stretched hole struggled to accommodate the new girth. 

Keith gasped, and in surprise, started to pull away, but Shiro held him steady. 

“What is that?” 

“Me trying to keep up with your needy ass.”

The device hummed for a moment as Keith settled around it. Then it clicked and Shiro saw its internals glow as the semi-transparent silicone plating pieces shifted from overlapping one another, pushing out wider. Keith held still, but the tension in his body was obvious. 

“Say if it’s too much.”

Keith’s only reply was to widen the stance of his knees.

The device stopped growing, then paused. There was a sudden pressure against Shiro’s thighs and he knew it had extended further into Keith.

Keith made a squeak, throwing his hands out to keep himself from face-planting into the pillow. A whirr of retreat, a pause, then again. Keith cried out.

“Keith-” Shiro was on full alert, ready to pull out immediately, or flip the switch, but Keith arched his back, spreading his body out across the sheets in supplication.

“Deeper!”

“It’ll ramp up.”

And it did. With every thrust, the time in between got shorter, and Shiro had specifically programmed it to kaleidoscope out into a longer shape. As the alien tech toy did all the work, he held Keith’s hips flush against his own, his cock leaking onto Keith’s ass, the precome pooling in one of Keith’s dimples as it rolled across smooth skin.

Keith started to flail.

“Too much?”

“Just right!”

Then Keith was shaking, hands fisted in the sheets.

“You can touch yourself, you know?”

“No! Want it to- want it to last! Please!”

Keith cursed and broke off, a violent shudder passing from his body to Shiro’s.

Shiro waited a few more thrusts, then let go of Keith’s right hip to flip the power switch. The toy immediately collapsed in girth, returning to a reasonable size, and Shiro pulled out.

“Shiro!” Keith voice was shrill with outrage. “I need-”

Shiro didn’t care what Keith needed at that moment, however, completely unable to tear his eyes away from that dark, empty hole convulsing around nothing. His cock twitched as he wondered if actually thrusting and fucking Keith with the toy would have resulted in prolapse. Would the prolapse happen anyway once the tissue had a chance to swell after its extreme stretching?

He pushed the strap-on back inside, this time holding it tightly to his cock. There was an initial resistance, then the rim reformed around the intrusion and let him inside. Keith moaned, all frustrated, angry tension slipping from his shoulders as he got his limbs under him again to push back onto Shiro.

“Fuck. So big.”

Shiro pulled Keith all the way onto himself, shuddering and fighting off black spots in his vision as he tried to keep himself in one piece. Hoping he didn’t fuck up with fumbling fingers, he pressed a couple toggles on the base of the toy and flipped the switch to on again.

The buzzing started immediately. Incapacitated immediately by the heavy, near-painful vibrations all along his underside, Shiro found himself breathing heavily and drooling onto Keith’s shoulder blade. 

Keith was a mess beneath him, writhing and struggling. Shiro had tried to fine tune the vibrations to be gentler, but eventually had to give up, too impatient to put the whole device together. He was just about to regret it when through the roaring of blood rushing past his eardrums, he picked up small mewls of  _ “Yes!” _ from beneath him.

The toy was getting bigger again and Shiro tried to hold on as the pressure on his cock increased-

He gasped, long and rattling, his vision blacking out entirely as orgasm surged. He bucked, and hearing Keith’s cries at the force, bucked harder, his hips out of his control.

Shuddering as he regained splotchy technicolor vision, he peeled himself off Keith, needing space to fill his lungs.

The vibration was too much,

Without thinking, he made to back off, only to have Keith’s nails viciously dig into his hip. An angry shout chased him and forced him still. Confused, Shiro meant to obey before he realized that he would go insane from the overstimulation if he stayed. Suddenly desperate, he struggled with the straps to release him from the contraption as the silicone plates spread wider and wider-

He pulled away with a gasp, Keith’s nails leaving behind awful scratches.

Then, responding before Keith’s whine was even fully formed, he leaned in to press a couple buttons.

The thrusting started back up again and Shiro had to brace his palm against the base of the toy to keep it from propelling itself out. Keith choked and wheezed out a moan, back arching and fingers clawing at the sheets.

Shiro couldn’t imagine it. The length and girth combined with the vibrating and thrusting-

Keith came with a sudden jerk, his hips going to the side and out of Shiro’s grip, still trying to roll back onto the giant dildo even as it slipped further out of him with each thrust.

Shiro finally managed to grab hold of it, switching the thrusting and vibration off as he held it steady for Keith to ride out the rest of his climax. As Keith’s body slowly stilled, he turned the power off, letting it compact back into its stasis size.

Shiro pulled the toy out, setting it aside before collapsing half on top of Keith, gathering him up into his arms.

“That finally hit the spot?”

Keith groaned, not even trying to turn around and kiss Shiro like he usually did after sex.

“Tell you when I remember enough English.”

 


End file.
